mau5 wrote:
mattce wrote:
Thought this was a nice question:
Is (7+x)/(8+x) ≥ 7/8?
(1) x <= 0
(2) x >= 0
Is (7+x)/(8+x) ≥ 7/8?
(1) x <= 0
(2) x >= 0
From F. S 1, assume x = 0. Thus, the question stem would read as IS 7/8≥ 7/8 ; we get a YES.
Again, assume x = -7, and the question stem would read as IS 0≥ 7/8 ; we get a NO. Insufficient.
From F.S 2, we know that (8+x) will ALWAYS be positive. Thus, we can safely cross multiply and the question stem would read as :
IS 8*(7+x)≥ 7*(8+X) --> IS 8x≥ 7x --> IS x≥ 0 ; This is always true. Sufficient.
B.
It's a great explanation